Nicolas D. Boscher

Robust bio-inspired antibacterial surfaces based on the covalent binding of peptides on functional atmospheric plasma thin films

Here, we describe a robust process aiming at conferring antibacterial properties on stainless steel through the covalent grafting of nisin, a natural antimicrobial peptide, onto a functional plasma thin film deposited by an atmospheric pressure dielectric barrier discharge process. The three different steps of the procedure, namely the deposition of a carboxyl rich thin layer, the surface activation by using a zero-length crosslinking agent and the nisin immobilisation, are reported and thoroughly characterised. A correlation between the carboxylic group surface concentration and the surface roughness onto the antibacterial properties of the layers is evidenced. Finally, IR analyses appear as a powerful analytical tool allowing us to validate the different chemical surface modifications, to confirm the relevance of the activation step to achieve a stable and homogenous peptide grafting over all the surfaces, as well as to investigate the secondary structure of immobilized peptides.

Atmospheric pressure plasma-initiated chemical vapor deposition (AP-PiCVD) of poly(diethylallylphosphate) coating: a char-forming protective coating for cellulosic textile.

An innovative atmospheric pressure chemical vapor deposition method toward the deposition of polymeric layers has been developed. This latter involves the use of a nanopulsed plasma discharge to initiate the free-radical polymerization of an allyl monomer containing phosphorus (diethylallylphosphate, DEAP) at atmospheric pressure. The polymeric structure of the film is evidence by mass spectrometry. The method, highly suitable for the treatment of natural biopolymer substrate, has been carried out on cotton textile to perform the deposition of an efficient and conformal protective coating.

A Novel Dry Chemical Path Way for Diene and Dienophile Surface Functionalization toward Thermally Responsive Metal–Polymer Adhesion

In this paper, we report a new and easily up-scalable dry chemical method to functionalize with diene and dienophile groups a large range of surfaces, such as metal, polymer, or glass, and we demonstrate the potentiality of this technique to realize thermally responsive adhesion between these materials. A complete and extensive surface chemistry analysis of the grafted surfaces, based on the deposition of an anhydride-rich thin plasma polymer layer by using an atmospheric pressure dielectric barrier discharge (DBD) plasma process, and its subsequent gas phase aminolysis reaction with specific diene or dienophile compound is discussed. The optimization of the assembling condition for these tailored surfaces has led to achieve a Diels-Alder adhesion force up to 0.6 N/mm at ambient temperature, which can be reduced by a factor of 50 when the retro Diels-Alder is ignited at a heating temperature around 200 °C. The study of the failure interface produced after peeling tests is presented and a mechanism of failure is proposed, based on forensic analyses involving surface analytical techniques such as XPS, ToF-SIMS, and SEM combined to AFM analyses for the retrieving of chemical and morphological information.

Metal–organic covalent network chemical vapor deposition for gas separation

The chemical vapor deposition (CVD) polymerization of metalloporphyrin building units is demonstrated to provide an easily up-scalable one-step method toward the deposition of a new class of dense and defect-free metal-organic covalent network (MOCN) layers. The resulting hyper-thin and flexible MOCN layers exhibit outstanding gas-separation performances for multiple gas pairs.

Functionalizable and electrically conductive thin films formed by oxidative chemical vapor deposition (oCVD) from mixtures of 3-thiopheneethanol (3TE) and ethylene dioxythiophene (EDOT)

Mixtures of 3-thiopheneethanol (3TE) and 3,4-ethylenedioxythiophene (EDOT) were used as the reactants for oxidative chemical vapor deposition (oCVD). Monomer (3TEu2006:u2006EDOT) feed ratios of (3u2006:u20061), (3u2006:u20062), (3u2006:u20063), (2u2006:u20063), and (1u2006:u20063) were employed to obtain conductive polymer thin films with varying densities of hydroxyl pendant groups. The incorporation of both 3TE and EDOT units into the deposited films was confirmed by a combination of high resolution mass spectrometry, UV-visible-Near Infrared (UV-vis-NIR), and Fourier transform infrared (FTIR) spectroscopy, yielding conductive and –OH functionalized thin films. Theoretical analysis of the initial formation of dimers was studied by using density functional theory (DFT). The calculation predicts that the reaction of 3TE and EDOT is kinetically favored over the combination of two 3TE monomers. The π–π* transition observed at 425 nm in the UV-vis-NIR spectra of the 3TE polymerized film red shifts with increasing EDOT incorporation. This transition is observed at 523 nm in the film prepared using (1u2006:u20063) a monomer feed ratio.

Chemical vapour deposition of metalloporphyrins: a simple route towards the preparation of gas separation membranes

A simple and easily scalable approach towards the preparation of gas separation membranes is described. UV-vis spectroscopy and size-exclusion chromatography undoubtedly evidenced the polymerisation of porphyrin building units and highlighted the significance of the proposed initiated plasma-enhanced chemical vapour deposition approach. The porphyrins are further copolymerised with a cross-linking agent, i.e. divinylbenzene (DVB), to form dense and microporous P(DVB-co-ZnTPC) thin films with enhanced chemical stability and superior gas separation properties. The gas separation performances for CO2/CH4, H2/N2 and H2/CH4 reach 150, 224 and 550, respectively, indicating that the P(DVB-co-ZnTPC) thin films have great potential applications for natural gas sweetening and hydrogen separation.

Dual Application of (Aqua)(Chlorido)(Porphyrinato)Chromium(III) as Hypersensitive Amine-Triggered ON Switch and for Dioxygen Activation

Although synthesis and substitution reactions of chlorido chromium(III) porphyrins Cr(III)(TPP)(Cl)(L) (H2TPP = 5,10,15,20-tetraphenyl porphyrin, L = pyridine, H2O, ROH, etc.), have been well-established in coordination chemistry for decades, an unexpected dichotomous reactivity of Cr(III)(TPP)(Cl)(H2O) (1) toward amines is disclosed here. This reactivity leads to the application of 1 as highly sensitive substoichiometric and irreversible ON switch for amine detection by an autocatalytic pathway. The concomitant activation of O2 by the 1/amine system is furthermore exploited in an electrochemically driven epoxidation of norbonene using O2 as initial oxidant.